I posted this elsewhere, but I'll share my thoughts again...
I agree the yellow looks fantastic for photography purposes, but is otherwise my least favorite of the color options.
I like to be able to camp discreetly, so I think the olive brown is pretty cool. Had I known that was a color option when I ordered my Trailstar a little over a year ago, I would've gone with it. Somehow I missed it and instead I ended up with the default gray. The gray isn't bad, I don't mind it really, since it's just a shelter, but if I did it over, I'd go with the olive brown for a darker tone and to add a little variety to my (entirely) gray shelter collection.